I don't know any particular pattern, so i am just guessing. Try to find say the first and second derivative of this function.And after that see if you can find any linear combination equal to zero,or to sth else, of second, first and the originall function

Basically your objective is to eleminate the parameters, here a and b, by differentiating and algebraically manipulating the equations. Typically, you will need as many derivatives as you have parameters to do that. Since you have two parameters here you would expect to result in a second order differential equation.